新型气固环流反应器内颗粒流动的CFD模拟

采用基于结构的EMMS曳力模型，对一种新型气固环流反应器中的颗粒流动特性进行数值模拟。模拟的固含率与颗粒速率预测值与实验数据具有一致性，验证了模型的适用性。模拟结果表明：导流筒表观气速增加，导流筒中的床层固含率减小，向上的颗粒速率增加；反应器中存在多个颗粒逆流和错流混合区，促进了颗粒沿径向的混合；槽孔处，导流筒中的固含率以及颗粒速率分布更加均匀，而环隙中存在颗粒浓集区；进料区在0≤L≤0.058 m，0< r/R< 0.3的范围内固含率增加并且颗粒存在明显的径向流动。

CFD simulation of particle flow in new type of gas-solid air loop reactor

The behavior of particle flow in a new type of gas-solid air loop reactor (GSALR), which acted as a particle mixer, was numerically simulated by multi-scale computational fluid dynamics (CFD) with the structure-dependent EMMS drag model. The suitability of the drag model was verified by agreement of the simulated results and the experimental data in time averages of solid holdup and particle velocity. The particle upward velocity increased but the mean solid holdup on beds decreased when the superficial gas velocity increased in the draft tube. Several mixing regions of particle crossflow and mixed flow in GSALR improved the efficiency of radial particle mixing. In the groove region, the distributions of solid holdup and particle velocity were more uniform, while a particle concentrating area was formed at circular overlap due to particle flow from the groove. In the region of 0≤L≤0.058 m and 0< r/R< 0.3, the solid holdup was increased and particle flow was evidently enhanced along the radial direction.